As his son recovered from a traumatic brain injury, Walter De Brouwer was prototyping a device that could upend the broken health care system. Here the serial entrepreneur describes how he ushered the idea from "Star Trek" to startup.

Naveen Jain is a serial entrepreneur whose work has spanned fields as diverse as web security, space exploration, and education and global development, so he knows a lot about problem solving. Here are some of his thoughts.